Analog amplifiers are incorporated into a vast number of devices used in everyday life. For example, analog amplifiers are used in automobile engines, cellular telephones, magnetic hard disk drives, fiber optic communication systems and even children's toys.
Unfortunately, analog amplifiers often suffer from a number of performance shortfalls. For example, analog amplifiers are subject to a trade-off between available voltage gain and frequency bandwidth. This trade-off, often referred to as the amplifier's “gain-bandwidth product”, may remain nearly constant over the operating range of the amplifier.
Additionally, the proliferation of hand-held devices, such as cellular phones and personal digital assistants (PDAs), has added another demand in that analog amplifiers must be increasingly energy efficient. Unfortunately, the gain-bandwidth product of an analog amplifier is often dependent on the current it consumes. Thus, every decrease in current consumption may reduce the amplifier's gain-bandwidth product. Accordingly, it should be appreciated that even modest current savings may cause a particular amplifier to attenuate high-frequency signal components to the detriment of the system incorporating the amplifier.